you will need 2x 6mmx40mm pins to secure this hook, the same that come with the shelves are fine, or you can use any 6mm rod, or you can secure with screws instead
edit: I added files for a pin to secure in place if you don't have the IKEA ones spare
This is designed to clip in place and the pins will stop it moving up and down
The clip will also rest on a shelf with no pins or screws
the .f3d file has some other tests I did included as other components, they all kinda worked ok too.
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The author hasn't provided the model origin yet.